Thermally insulated conduit

ABSTRACT

Thermally insulated conduit of indefinite length for transporting liquid or gaseous material in a heated or cooled state; the conduit including an oscillation damping layer.

UnIted States Patent I151 3,698,440 Matthieu et al. I 1 Oct-17, 1972[541 THERMALLY INSULATED CONDUIT [58] Field ofSearch .138/26, 149, 114,121122; [72] Inventors: Paul Matthieu, Berlin; Ottmar' 252/62; 161,139;181/47 36 B Leuchs, Hannover; Fritz Glander, Isernhagen NB; HubertKuypers, [56] References d Bad Nenndorf; 'Diethart Pelz, Lan- UNITEDSTATES PATENTS genhagen Germany 3,473,575 10/1969 Vogelsang.......138/149 [73] Assignee: Kabel-uud Metallwerke Guteholf- 3,561,4922/1971 Kauder ..138/ 121 h tt Akti llsch tt l-l g f FOREIGN PATENTS ORAPPLICATIONS 2 Filed: April 20 1971 769,993 3/1957 Great Britain..i81/47 A [21] Appl. N 3 5 Primary Examiner-Herbert F. Ross IAttorney-Phillip G. Hilbert [30] Foreign Application Priority DataABSTRACT 1970 Germany 20 19 0812 Therrnally insulated conduit ofindefinite length for I transporting liquid or gaseous material in aheated or [52] US. Cl. ..l38/l49, 138/26, 138/114, coaxed state; theconduit including an oscillation 138/122, 181/36 B, 181/47 A, 252/62,damping ]ayer 161/139 [51] Int. Cl ..Fl6l 9/14, F16] 59/02, F16] 55/04 7Claims, 2 Drawing Figures THERMALLY INSULATED CONDUIT The instantinvention relates to thermally insulated conduit which is used totransport liquid or gaseous materials in a heated or cooled condition.Such conduit consists of at least two corrugated concentric tubings.

Such conduits are particularly used for long distance heating andusually include a heat insulating layer such as polyurethane foamdisposed between inner and outer tubings. Such conduit can be made inlong lengths and lends itself to shipment wound on drums in a mannersimilar to that used for electrical cables.

However, a disadvantage resides in known conduit constructions whereinthe tubings are corrugated to in crease flexibility thereof. Thus, withvery long lengths of conduit and-at certain rates of flow of the mediapassing through the inner tubing; such inner tubing is stimulated andswings in its longitudinal axis because of the corrugations thereof.

Accordingly, an object of this invention is to provide a thermallyinsulated conduit comprising a pair of concentric corrugated tubings,together with a layer of oscillation damping material therebetween.

Another object of this invention is to provide an improved conduit ofthe character described, which further includes a layer of heatinsulating material.

Yet another object of this invention is to provide a conduit of thecharacter described, wherein the oscillation damping layer also has heatinsulating characteristics.

Other objects of this invention will in part be obvious and in parthereinafter pointed out.

DESCRIPTION OF THE DRAWING FIG. 1 is a longitudinal sectional view of athermally insulated conduit embodying the invention;

FIG. 2 is a transverse sectional view thereof DESCRIPTION OF THEPREFERRED EMBODIMENTS As shown in the drawing, designates a thermallyinsulated conduit embodying the invention. The same comprises an innertubing 1 which may be formed of copper or other suitable materialincluding synthetic resin foil. The tubing 1 is transversely corrugated.

Disposed about tubing 1 is a tubing 2 concentrically related thereto andwhich may be formed of steel and derived from a metal tape converted toa tubular form about inner tubing 1, with a longitudinal slit therein toprovide a longitudinal seam which is thereafter welded in a knownmanner. A layer 3 of oscillation damping material is introduced betweentubings l and 2, by way of the slit portion in tubing 2. The tubings 1and 2 are held in spaced relation by a helical supporting strip 4 ofplastic or other suitable material.

The damping material 3 is of a thixotropic nature and may suitablyconsist of a hydrous dispersion of polyvinyl acetate which is filledwith vermiculite flake or particles. The material 3 may be furtherloaded with powdered barium sulfate.

Further, conduit 10 may include an outer sheath 5 which is formed ofsteel from a tape folded about tubing 2 and longitudinally seamed ina-known manner, as by welding or the like. Disposed between sheath 5 andtubing 2 is a layer of heat insulating material 6 such 'as hardpolyurethane foam. Spacer means 7 is also provided between tubing 2 andsheath 5, in the form of a helical str p of plastic or the like, whichis introduced by way of the slit portion of sheath 5 as the same isformed. I

On the outer surface of sheath 5 there is disposed a corrosioninhibiting layer 8 followed by an extruded jacket 9 of polyvinylchloride or other suitable resin.

,It has been found that the Thixotropic material 3 increases itsplasticity when the conduit is subject to sudden deformation asincipient oscillations, and thus is effective to dampen suchoscillations. Also, the layer 3 along the length thereof may comprisealternating sections of hard and soft material, which also acts as adamping means to break up any oscillation system.

It is understood that a single layer of material may be used in theconduit which exhibits both oscillation damping characteristics and isalso a thermal insulator.

We claim:

1. A thermally insulated conduit for transporting liquids or gases in aheated or cooled state, said conduit comprising a pair of concentric,transversely corrugated tubings providing an annular space therebetweenand a layer of oscillation damping, thixotropic material in said spaceand in contact with the innermost of said tubings.

2. A thermally insulated conduit as in claim 1 and further including alayer of heat insulating material disposed outwardly of said thixotropicmaterial.

3. A conduit as in claim 1 wherein said tubings are formed of metal.

4. A conduit as in claim 1 wherein at least one of said tubings isformed of synthetic resin.

5. A conduit as in claim 1 wherein said thixotropic material comprisessuccessive longitudinal sections of alternating hardness and softness.

6. A conduit as in claim 1 wherein said thixotropic material comprises ahydrous dispersion of polyvinyl acetate filled with vermiculite.

7. A conduit as in claim 6, and further including a filler of powderedbarium sulfate in said dispersion.

1. A thermally insulated conduit for transporting liquids or gases in aheated or cooled state, said conduit comprising a pair of concentric,transversely corrugated tubings providing an annular space therebetweenand a layer of oscillation damping, thixotropic material in said spaceand in contact with the innermost of said tubings.
 2. A thermallyinsulated conduit as in claim 1 and further including a layer of heatinsulating material disposed outwardly of said thixotropic material. 3.A conduit as in claim 1 wherein said tubings are formed of metal.
 4. Aconduit as in claim 1 wherein at least one of said tubings is formed ofsynthetic resin.
 5. A conduit as in claim 1 wherein said thixotropicmaterial comprises successive longitudinal sections of alternatinghardness and softness.
 6. A conduit as in claim 1 wherein saidthixotropic material comprises a hydrous dispersion of polyvinyl acetatefilled with vermiculite.
 7. A conduit as in claim 6, and furtherincluding a filler of powdered barium sulfate in said dispersion.